1. Field of the Invention
The present invention relates to a vehicular active sound control system for generating a sound effect in a vehicle depending on a running state of the vehicle, and more particularly to a vehicular active sound control system for outputting a sound effect based on a control signal depending on the rotation frequency of the engine of a vehicle, into the vehicle.
2. Description of the Related Art
There have heretofore been proposed active sound control systems for detecting an accelerating or decelerating action made by the driver of a vehicle and outputting a control signal depending on the acceleration or deceleration, as a sound effect from an output means such as speakers into the vehicle (see Japanese Laid-Open Patent Publication No. 63-43494 and Japanese Patent No. 3261128).
Since such an active sound control system is not a standard equipment system in the vehicle, the active sound control system is installed separately from an audio system in the vehicle.
If the output means for producing a sound effect for the active sound control system is shared by the audio system and the active sound control system, then the control signal depending on the acceleration or deceleration which is output from the active sound control system is combined with an audio signal from the audio system by an adder, and the combined signal is output as combined sounds (sounds depending on the sound effect and the audio signal) from the output means into the vehicle.
The output means includes door speakers mounted in the doors on the sides of front seats of the vehicle and rear speakers mounted behind the rear seats. When a sound effect depending on the running state of the vehicle, i.e., the rotation frequency of the engine, is output from these speakers into the passenger compartment of the vehicles, the passengers on the vehicle feel uncomfortable with the sound effect because the passengers hear the sound effect coming from the sides of the front seats or from behind the rear seats despite the fact that the engine is located in a front portion of the vehicle and hence the passengers tend to judge that the sound effect is not created depending on the rotation frequency of the engine.